﻿<!DOCTYPEHTML>  
<html>  
<head>  
<metahttp-equivmetahttp-equiv="Content-Type" content="text/html;charset=utf-8" />  
<title>if...else</title>  
<script type="text/JavaScript">  
var score =78;      //score变量存储成绩，初值为80  
if(score<60){  
document.write("成绩不及格。");  
}else if(score>=60 && score<=70){ 
document.write("成绩及格。");  
}else if(score>70 && score<=80){ 
document.write("成绩良好。");  
}else{ 
document.write("成绩优秀。");  
}   
</script>  
</head>  
<body>  
</body>  
</html>
